anomics, with and without semantic comprehension disorders (SCD). ... patients, narnely in patients with anomic aphasia, word-fmding disturbances can bc.
APHASIOLOGY, 1989, VOL. 3, NO. 5, 423-434
Semantic field integrity and naming ability in anemie patients MARIA C A T E R I N A S I L V E R I , 'SERGIO CARLOMAGNO, UGO NOCENTINI, 'SERGIO CHIEFFI and "GUIDO G A I N O T T I Ncuropsychology Service-Iris ti tu te of Neurology, Catholic University, Roma 'institute of Neurology, I Faculty, University of Napoli "Institutc of Neurology, II Faculty, University of Napoli (Received 7 May 1987; revision reteivcd 3 June 1988; aaepted 24 Augmt 1988}
Abstract Goodglass arid Baker had suggested chat in aphasia with verbal comprehension disordcrs some components of thè seraantic fields assocìated with ohject names are selectively undcrmined, and that thè ability to namc a particular object should be subserved by thè integrity of its semantic tìeld. We tricd, cmployìng an Association Task in which subjccts judgcd whether or not a word was rclatcd to a target, to replicate these results by focussing our attention on two populations of anomics, with and without semantic comprehension disorders (SCD). Anomics with SCD periormcd worse 011 thè Association Task thaii anomics without SCO arid controls but, contrary to Goodglass and Baker's data, no impairment of particular associative categories in thè thrcc groups was found. Furthermorc, no quantitative or qualitative differences werc found bctween scores obtained on associatiotis to corrcctly named and not named targcts on both anemie groups.
Introduction Many studies have investigatcd, using a largc varicty of methodologies, several aspects of semantic disorganization in aphasia (Ilowes 1967, Lhermitte, Dcroucsnc and Lecoursy 1971, Zurif, Garamazza, Mycrson and Galviii 1974, Coughlan and Warrington 1978, Whitehouse, Caramazza and Zurif 1978, Grobcr, Pcrccman, Kcllar and Erown 19HO, Grossman 1981, Caramazza, Berridt and Erownell 1982). However, thè relatìoii between semantic organization and ability in cvoking thè corrcct name of an object has not ofteri been considered. In one of thè studies which have tackled this problem, Goodglass arid Baker (1976) took into account thè qualitative changes in semantic organization of fluent aphasics and, specifìcally, thè effect of a rcduccd semantic ficld on thè ability in naming. Previous observations by Goodglass, Barton and Kaplan (1968) had suggested that thè ability to name a particular object is subserved by thè convergence of information from rnany sensory modalities which could act by arousing thè 'conccpt' of thc object. Since inner semantic associates certainly concur with sensory attributes to elaborate thc full semantic representation of an object, Goodglass and llaker (1976) assumed that "deficiencies in thè semantic network of associations to particular words would bc related to impaircd ability to cvokc thc names for those words". This hypothesis was Address for correspondcncc: Maria Caterina Silvcri, Neuropsychology Service, Institute of Neurology, Catholic University, Largo A. Gemelli 8, 00168 Roma, Italy. 0268-7838/89 SJ.OO © 1989
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tested by adopting a methodology based on thè rccogriition of vcrbal associate^ beloiiging co differcnt catcgories of semantic relations, to cxplore thè semantic organization in High and Low Comprchcnsion aphasìcs. In low coniprehension patients, Goodglass and Baker (1976) demonstrated, in accordancc with thè hypothcsis, a significant relation between not namcd itcnis and disruption of their semantic associations. A second finding of this rescarch was that not ali thc componcnts of thc semantic field are equally impaircd in low comprehension aphasics. The- superordinate (e.g. 'instrumcnt 1 if thè target is a drum), attributo (c.g. drum—'loud') and contrast coordinate (e. g, drum—'guitar 1 or anothcr member of thè sanie superordinate class) relations are rclativcly spared, whereas thè function associate (i.e. thè action typically carried out upori thè target, e.g. drum—'beat') and thc functional context relation (i.e. thè contcxt in which an object is usually found, e.g. drum—'band') are particularly impaired. On thè basis of these fìndings, Goodglass and Baker (1976) concludcd: (a) that ability in naming is partly dctermined by thè convergence of thè relcvant semantic associatesi (b) that low comprehension aphasics show a qualitative change in thcir semantic field organization; (e) that a one-to-one relation has to he admitted in low comprehension aphasics between ability in retricving thc nanic of a particular item and thè integrky of its semantic associative network. Thè hypothcsis of Goodglass and Baker (1976) has bccn subjcctcd to a new experimental verification by McClcary and Hirst in a recent study (1986). They cxplorcd, by using a classification task of both words and picturcs, thc ability to appicciate three types of semantic relations ('basic level' e.g. kinds of chairs; 'superordinate' c.g. kinds of furniture; 'function' e.g. things that cut). Thcir rcsults were only in partial agreement with Goodglass and Baker's data since no selective impairment was obscrvcd in fluent aphasics, when compared with non-flucnt aphasics and controls. Only quantitative, and not qualitative, diffcreiices were in fact observed among thè three groups. Furthermore. a relationship between thè ability to namc a givcn itcm and thè ability to correctly classify that itcm was found only for thè basic level, but not for thè superordinate and thè function level items. The partial disagreement bctwccn thcsc twro studies could be due to thè fact that thcy had been conducted on poorly defìned samplcs of aphasic patients, contrasting High Comprehension with Low Comprchension and fluerit with non-flucnt aphasics, rcspcctivcly, so that thè observed word finding disturbanccs could result from a heterogeiieous set of mcchanisms. In a recent paper, Gaìnotti, Silveri, Villa and Miceli (1986) havc, indeed, shown that even in a more homogcncous sample of aphasic patients, narnely in patients with anomic aphasia, word-fmding disturbances can bc subscrvcd by two different sets of mechanisms. Anomics with Icxical comprehension disorders demonstrateno tacit knowlcdgcofthe phonological forni of words theyare unable to retrievc and produce a certain number of verbal-semantic paraphasias in addition to anomia proper. Since thcy do not show phoiiemic discrimination disorders at thè receptive levcl, thcir naming and lexical comprehension disturbanccs sccm due to a cominoli mechanism, naniely a nuclcar semantic deficit. By contrast, in anomics without lexical comprehension disorders thè defect cunsists of an almost pure inability to fmd thc intcnded word, without associated semantic crrors and with some evidence of a tacit knowledge of words which thè patient fails to name. These fìndings seem to suggest that in this variety of anomia thè locus of defect is not within thc semantic systcm (as in anomics with lexical comprehension disorders) but mudi nearer thc stage in which thc lexical item correspondirig to thè aroused semantic
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rcpresencation is sclccted and encoded into thè appropriate phonological form. Sincc thè nuclear scmantic deficit of anomics with lexical comprehension disorders could just consist of a disruption of thè semantic field, similar to thac described by Goodglass and Baker (1976), wc considered thè problem of thè relationship between anemia and scmantic disorganization, by contrasting results obtained from anomics with and without lexical comprehension disorders, on an Association Task similar to that adopted by Goodglass and Baker (1976). The main scopes of our experimcnt can, therefore, be formulated as follows: (1) To explorc thè status of thè scmantic organization in anomics with scmantic-lexical comprehension disorders (SCD), dctcrmining ifa qualitative change exists in thcir semantic fìelds and if this change is consistent with that observed by Goodglass and Baker (1976). Results obtained by anomics with SCD in thè various associativc categories were, therefore, compared with thosc obtained in thè same situation by normal controls and by anomics without SCD. (2) To determine i f a relationship between inability to name a given item and disruption of thc corresponding semantic ficld can be observed in anomics with SCD, but not in those free from comprehension disorders. Thc following predictioiis wcrc made: (a) Tf thè semantic deficit of anomics with lexical comprehension disorders consists of a 'structural' change affccting thè semantic field of particular items {as thè Goodglass and Baker data implicitly suggest), thcn thè verbal associations relative co thè corrcctly named items should be recognized better than thc associations relative to thè not named itcms. A similar difference should not be observed in anomics wìchout SCD, since in these patients thc semantic System is supposed to be intact. (b) If, 011 thc other hand, thè semantic deficit of chese patients consists of a more diffuse loosening of thc scmantic relations or of a more dynamic inability to acccss in generai thè scmantic representations, thcn anomics with SCD (although being overall more impaired than anomics without SCD on thc verbal Association Task) should not prescnt a selective impairment of thè semantic associatcs relative to thè not named items. Method Stimuli Naming Test Forty coloured pictures, drawn from ten common scmantic categories (furniture, clothirig, vehiclcs, toys, kitchen utensils, domestic animals, wild animals, insccts, fruita, flowers) were choscn. The iiames of thè 40 itcms belonged to thc mediurn-high range of word-frequency and of prototypicality withiii thc superordinate catcgory. Association Task Por each of thè 40 pictures of thè Naming Test (targets) wc sclccted, on thè basis of thè responses obtained 011 prctcsting a population of 20 riorrnal subjccts, 'thè best associate' for each of thè following six associative categories: - superordinate - part of whole - attribute
c.g. e.g. e.g.
cat/animal orangc/scgment tiger/wild
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~- function - functional contcxt - contrast coordinate
e.g. e.g. e.g.
dog/to bark lion/forest cat/dog
The 240 (6 X 40) verbal associations were randomized with 240 filler-words bclonging to thè same grammatical classes, producing a list of 480 words that were divided into four blocks each of 120 stimuli.
Procedure The picturcs of thè Naming Test were first admìnistered in fixed randorn ordcr tocach subject; thè patient had to narne thè itcnis without any cue. In case of narning failure, thc sufajcct was requested to demonstrate recognition by gestures, or by any other means. The Association Task was administered in four sessions lasting about 30 minutes each; thè words were presented to each subject onc-by-one for 3000 ms in a fixed random ordcr on a video-display connected to an Apple III computer. Each association word was preceded by thè presentation of thè corresponding picturetarget, whosc name was pronounced aloud by thè examiner to ensure that thc subject understood thè meaning of thè picturc. Thc subject had been instructed to squeeze a bulb as soon as s/hc found some relation between thè word and thc target. The right hand was used to squeeze thè response bulb, except in case of severe right hemiparesis. To minimize any memory problem, thc target rcmained before thè subject until a response was given. Accuracy and latency of each response was recorded.
Subject s Nine anonlic patients, of relatively young age (31-67 ycars) and good socio-cultural level (with 8-17 ycars of schooling) were selected from a chronic aphasic population according to thè following criterìa: (a) (b) (e) (d)
right haiidcdness, without any familial Icft handedness; preserice of a siiiglc, not too exterisive, left hemisphere lesion; abscncc of obvious clinical and CT scan sigiis of diffuse cortical daniage; presence of moderate to severe word-fmding disturbances in thè contcxt of flucnt speech without or with few paraphasic errors and with good comprehension at thè phrase level.
Twcnty subjects without ncurological lesions, and matched with anomics for agc and educational level, constituted thè control group. The presence of lexical comprehension disorders was cvaluated in ali these patients by means of a matching-to-sample technique, in which subjects chosc, from three semantically rclated pictures, one that corresponded to thè word spoken aloud by thc examiner or to thè word written in largc characters at thc bottoni of thè column formcd by thè multiple choicc alternativcs (Gainotti, Miceli, Caltagironc, Silveri and Masullo, 1981). The results of botri written and auditory forms of administration of thè comprehension tasks, uscd to distinguisi! anomics with and without lexical comprehension disorders, are reported in tablc 1, together with thè mairi demographic and clinical charactcristics of each patìcnt arid thè perccntagc of anomic responses obtaincd on thè naming task. Since no control subject iliade more than two errors {out of 40 stimuli) on thc lexical comprehension tasks, this scorc was takeii as thè cut-off point between normal
Table 1. Maìn characteristics of anotnics and controls. Errors (out of 20)
r°* C o\.loj urea
from onsct (months)
(out of 36)
Token test score (out of 36)
6
21
S
4
3
32-5
32 28 24
32-5 18 16
2 6
2 4
2
2
22-5 71 -H 40-0
8
Parietotemponil Teinporal
12 12 3 12
28
14
4
3
56-2
44
13
Temporal
12
31
34
0
0
37-5
DP
40
8
12
27
31
1
1
27-5
EC
58
16
Tempore— parictal Temporo— parietal
12
32
12
0
0
12-5
MM
57
17
12
33
35
0
0
32'5
Interval
Anomics
Patient
Age (ycars)
Schooling (years)
FF
61
17
ML LA DP
67 56 39
14 16 13
AA
31
FS
with SCD
Anomics without SCD
"Mami Whitney U-t
Lesiun
localization Parietotemporal Temporal Temporal
Teinporal
matriccs SCO re
Auditory language comprchcnsion
Rea din g comprchcnsion
Percentage of naming crrors
f 3 a 5 K-
=k 3
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Al C. Silveri et al,
and pathologìcal performanccs. Anomics with more than two errors were placed in thè cacegory 'with SCD1, whereas those with no more than two errors were considcrcd frcc from SCD. Data rcportcd in tablc 1 show that thc two groups are well distinguished as for thè number of lexical compreherision errors. Furthermore, thè sanie data show that a high dcgrec of ovcrlap was obscrvcd within cach individuai patient, across thè two modalìties of reading cornprehension, and in auditory language comprehensiori. This fmding suggests that Icxical cornprehension disturbances were due to a centrai scmantic impairrnent and not to peripheral causes such as visual or auditory discrimination disturbances. Scoring Naming Test Thc percentage of naming errors (anomias and semantic paraphasias) wcrc evaluated for each subjcct. Phoncmic distortions were not considered to be errors, sìncc thcy wcrc not due to a word fmding disordcr. Association Task For cach subject {anomics and controis) wc evaluated: (a) thè overall percentagc of correct resporises given on thc Association Task and their meati latcncy; and (b) thè percentagc of correct rcsponses and thè mean latencics to cach associative cacegory. For each subject we obtained thc 'ratio' between wroiig responscs 011 thè Association Task and on thc Naming Test, distinguishing rcsults obtained on thè narned and not-named items, according to thc formulae: Number of wrong associativc rcsponses on correctly named targets Number of correctly named targets Number of wrong associative responses on not-corrcctly named targets Number of not-correctly named targets
Results Test Allpatients ofbothanomic groups showed clear difficulties in naming (table 1). Even if anomics with SCD were generally more severely impaired than anomics without SCD, this diffcrcncc did not rcach thc Icvcl of significaiice (Mann Whitncy L-'-test: z = 1-37- p = 0-18). Association Task Whcn thc overall number of correct responses given on thc Association Task was taken irito accourit (table 2), anomics with SCD showed a significantly lower score than botri anomics without SCD (z = —6; /)
